The Next Frontiers in Rare-Event Detection for Science and Security

Project Overview

Accurate, nonintrusive tools for the direct monitoring of nuclear reactors would benefit international safeguards, especially as advanced reactor types that challenge conventional techniques come online. One technological approach to this problem is the detection of antineutrinos emitted by nuclear reactors. While challenging to detect, these particles carry information about reactor operational state and fuel content and cannot be shielded or obscured, and measurement requires no connection to a facility. To broaden the utility of antineutrinos, our goal was to lay the groundwork for detection systems able to precisely and nonintrusively monitor any nuclear reactor.

This work had three major thrusts. First, we have improved the ability to predict reactor antineutrino emissions. This has been accomplished through the development of the CONFLUX software package, which provides a flexible and well-documented capability to incorporate multiple nuclear-data inputs, compare prediction techniques, and establish an "industry" benchmark approach. Second, we have developed technologies to enable mobile antineutrino detectors with the ability to operate on the earth's surface. New large-scale Li-6 doped plastic scintillator materials that can select antineutrino interactions and reject backgrounds have been developed and transferred to an industry partner. A prototype detector using these materials has been constructed and installed in a mobile platform. Third, we have demonstrated a technique to improve low-threshold detection in liquid argon, which could enable more compact antineutrino detectors using the coherent neutrino nucleus scatter interaction. For the first time, stable doping of percent levels of xenon into liquid argon has been achieved, improving its utility as a detection medium. Each of these thrusts also has potential scientific impact, providing antineutrino source term information for scientific measurements that seek to use the intense antineutrino flux from reactors; enabling high-sensitivity measurements close to nuclear reactors searching for hypothesized sterile-neutrino particles and providing precision reference antineutrino measurements; and enabling searches for low-mass dark matter.

Mission Impact

This work has developed science and technology tools and capabilities to meet future national-security challenges and advance our nation's scientific enterprise. The CONFLUX antineutrino prediction package will support a wide range of scientific and applied measurements at reactor facilities. The xenon doping technique developed here will improve the threshold and resolution performance of liquid argon time projection chambers (TPCs) for neutrino and dark matter physics, and pave the way for this technology to detect antineutrino coherent scatter at reactors. The Li-6 doped scintillator materials advanced here and transferred to industry will enable a new class of large-scale antineutrino and neutron detectors. Integration of these materials into a prototype mobile antineutrino detector will provide tools and techniques for systems able to make measurements at any reactor, both for nonproliferation applications and short-baseline neutrino physics. Through hiring and training, we have established new workforce capabilities at LLNL in detector engineering, cryogenic systems, materials science, and antineutrino and neutron-detection modelling and detection. Combined, these advances have resulted in new project support in both neutrino physics and nuclear security to build a new generation of reactor antineutrino detectors for operation at the earth's surface.

This work was performed in part under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-840223

Publications, Presentations, and Patents

Pereverzev, S. 2019. "Effects of Energy Accumulation in Materials: Self-Organized Criticality Dynamics in Low Energy Threshold Ionization Detectors for Coherent Neutrino Scatter, Dark Matter Searches and in Superconducting Sensors and Qubits." Presentation, Magnificent CEvNS 2019, Chapel Hill, NC. November 2019.

Bowden, N. 2019. "Dual Phase LAr Detector R&D for CEvNS Measurements at Reactors." Presentation, Magnificent CEvNS 2019, Chapel Hill, NC. November 2019.

Li, V. 2019. "PSD Capable Plastic Scintillators with Li-6 Doping for Neutron and Reactor Antineutrino Detection." Presentation, CPAD Instrumentation Frontier Workshop 2019. Madison, WI. December 2019.

Bowden, N. 2019. "Reactor Antineutrino Detector Development at LLNL using PSD Capable Plastic Scintillators with Li-6 Doping." Presentation, Applied Antineutrino Physics 2019, Guangzhou, China. December 2019.

Li, V. 2020. "SANDD: A Highly-Segmented Li6-Doped Plastic Scintillator Detector Incorporating Silicon Photomultiplier Arrays." Poster, APS April Meeting 2020. Washington, DC. April 2020.

Li, V. 2020. "SANDD: The development of a Highly-Segmented Plastic-Scintillator Antineutrino Directional Detector Incorporating SiPM Arrays." Poster, Neutrino 2020. Chicago, IL. June 2020.

Dazeley, S. 2020. "Reactor Antineutrino Detector Development at LLNL Using PSD Capable Plastic Scintillators with Li-6 Doping." Presentation, NuTools Mini-Workshop for the Applied Antineutrino Technology Community. Virtual. July 2020.

Xu, J. 2020. "A Xenon-Doped Argon Ionization Detector for CEvNS and Low-Mass Dark Matter Search." Presentation, DARPA SCRAM Workshop. Virtual. July 2020.

Xu, J. 2020. "What's Below the Energy Threshold of Noble Liquid TPCs." Invited Colloquium, UC Davis Physics Department, Davis, CA. Virtual. December 2020.

Pereverzev, P. 2020. "Dark Side of Afterglow." Presentation, Magnificent CEvNS 2020. Virtual. November 2020.

Li, V. 2021. "Towards Modular Compact Fast-Neutron and Reactor-Antineutrino Detectors Based on 6Li-Doped PSD Plastic Sscintillator and SiPM Arrays." Invited Colloquium at U. Hawaii Physics Department, HI. Virtual. March 2021.

Li, V. 2021. "Towards Scalable Fast-Neutron and Reactor-Antineutrino Detectors Based on 6Li-Doped PSD Plastic Scintillator and SiPM Arrays." Presentation, CPAD Instrumentation Frontier Workshop 2021. Stony Brook, NY. March 2021.

Bernard, E. 2021. "Improving the Proportional Scintillation Signal of Liquid Argon by Xenon Doping." Presentation, CPAD Instrumentation Frontier Workshop 2021. Stony Brook, NY. March 2021.

Bowden, N. 2021. "ROADSTR: a Mobile Antineutrino Detector Platform for Enabling Multi-Reactor Spectrum, Oscillation, and Application Measurements." Presentation, APS April Meeting 2021. Virtual. April 2021.

Roca, C. 2021. "PROSPECT: The Design and Expanded Physics Reach of the PROSPECT-II Detector Update." Presentation, APS April Meeting 2021. Virtual. April 2021.

Li, V. 2021. "Advances in Radiation Detectors Based on Finely-Segmented PSD Plastic Scintillator: From Fast Neutrons to Reactor Antineutrinos." Presentation, APS April Meeting 2021. Virtual. April 2021.

Bernard, E. 2021. "Improving the Ionization Response of Two-Phase Argon Detectors by the Addition of Xenon." Presentation, APS April Meeting 2021. Virtual. April 2021.

Mizrachi, E. 2021. "Development of a Xenon-Doped Dual-Phase Argon Time Projection Chamber." Presentation, APS April Meeting 2021. Virtual. April 2021.

Li, V. 2021. "Advances in Radiation Detectors Based on Finely-Segmented PSD Plastic Scintillator: From Fast Neutrons to Reactor Antineutrinos." Presentation, Technology and Instrumentation in Particle Physics 2021. Virtual. May 2021.

Roca, C. 2021. "Multi-Reactor Scientific Reach and Application Measurements with ROADSTR, a Mobile Antineutrino Detector." Presentation, APS DPF Meeting 2021. Virtual. July 2021.

Sutanto, F. 2021. "SANDD: A Directional Antineutrino Detector with Segmented 6Li-Doped Pulse-Shape-Sensitive Plastic Scintillator." Presentation, 2021 IEEE Symposium on Radiation Measurements and Applications. Virtual. May 2021.

Ford, M. 2021. "Development of PSD Plastic Scintillators." Poster, 2021 INMM/ESARDA Joint Annual Meeting. Virtual. August 2021.

Bowden, N. 2021. "ROADSTR: A Mobile Antineutrino Detector Platform for Enabling Multi-Reactor Spectrum, Oscillation, and Application Measurements." Presentation, 2021 INMM/ESARDA Joint Annual Meeting. Virtual. August 2021.

Xu, J. 2021. "Noble Element Detectors for Rare Event Searches." Invited review presentation, LIDINE 2021: LIght Detection In Noble Elements. Virtual. September 2021.

Pershing, T. 2021. "Direct Detection of Argon Scintillation Lght Using VUV-Sensitive Silicon Photomultipliers." Presentation, LIDINE 2021: LIght Detection In Noble Elements. Virtual. September 2021.

Bernard, E. 2021. "Preliminary Tests of Dual-Phase Xenon-Doped Argon Mixtures in the CHILLAX Detector." Presentation, LIDINE 2021: LIght Detection In Noble Elements. Virtual. September 2021.

Xu, J. 2021. "Status of the CHILLAX Detector Development." Presentation, Magnificent CEvNS 2021. Virtual. October 2021.

Roca, C. 2021. "Multi-Reactor Scientific Reach and Application Measurements with ROADSTR, a Mobile Antineutrino Detector." Presentation, IEEE Nuclear Science Symposium 2021. Virtual October 2021.

Bowden, N. 2021. "Nuclear Data for Antineutrino Detector Response." Presentation, 2021 Nuclear Data for Reactor Antineutrino Measurements Workshop, Virtual. June 2021.

Zhang, X. 2021. "Reactor Neutrino Spectrum Prediction: Nuclear Data Impacts and Interplays." Presentation, 2021 Nuclear Data for Reactor Antineutrino Measurements Workshop. Virtual. June 2021.

Zhang, X. 2021. "CONFLUX: A Flexible, Modular Reactor Neutrino Flux Calculation Framework." Presentation, 2021 Fall Meeting of the APS Division of Nuclear Physics. Virtual. October 2021.

Xu, J. 2021. "Where Does Dark Matter Hide?" Invited Colloquium at University at Albany, State University of New York. Virtual. November 2021.

Xu, J. 2021. "CHILLAX: A Xenon-Doped Dual-Phase Argon Detector for Rare EventSearches." Invited Seminar at Fermilab, Illinois, Virtual. April 2021.

Bernard, E. 2022. "Early Results from Xenon Doping of a Two-Phase Argon Time Projection Chamber." Presentation, APS April Meeting 2022, New York. April 2022.

Li, V. 2022. "Towards Directional Detection of Reactor Antineutrinos with Segmented 6Li-Doped PSD Plastic Scintillator: SANDD Status." Presentation, APS April Meeting 2022, New York. April 2022.

Kingston, J. 2022. "Characterization of Hamamatsu VUV4 Silicon Photomultipliers using Argon Scintillation." Presentation, APS April Meeting 2022, New York. April 2022.

Bowden, N. 2022. "Review of Experimental Reactor Antineutrino Flux and Spectrum Measurements." Invited review presentation, Neutrino 2022, Virtual. May 2022.

Dazeley, S. 2022. "ROADSTR: A Mobile Antineutrino Detector Platform for Enabling Multi-Reactor Spectrum, Oscillation, and Application Measurements." Poster, Neutrino 2022. Virtual. May 2022.

Zhang, X. 2022. "CONFLUX: A Flexible, Modular Reactor Neutrino Flux Calculation Framework." Presentation, Nuclear Data 2022. Virtual. July 2022.

Xu, J. 2022. "Photosensors for HEP Experiments." Invited seminar, HEPCAT Summer School, UC Davis, Davis, CA. June 2021.

Pershing, T., et al. 2022. "Performance of Hamamatsu VUV4 SiPMs for Detecting Liquid Argon Scintillation." Journal of Instrumentation, 17 P04017m (2021); doi: 10.1088/1748-0221/17/04/P04017.

Andriamirado, M., et al. 2022. "PROSPECT-II Physics Opportunities." J. Phys. G: Nucl. Part. Phys. 49, 070501 (2022); doi: 10.1088/1361-6471/ac48a4.

Sutanto, F., et al. 2021. "SANDD: A Directional Antineutrino Detector with Segmented Li-Doped Pulse-Shape-Sensitive Plastic Scintillator." Nuclear Instruments and Methods A.,1006, 165409 (2021); doi: 10.1016/j.nima.2021.165409.

Zaitseva, N., et al. 2020. "Multiple Dye Interactions in Plastic Scintillators: Effects on Pulse Shape Discrimination." Nuclear Instruments and Methods A., 978, 164455 (2020); doi: 10.1016/j.nima.2020.164455.